Whilst digital-to-analog conversion (DAC) is well known in the electrical domain, so far little attention has been devoted to DAC in the optical or photonic domain. The use of all optical DAC could be used to implement ultra-fast signal processing functions such as pattern recognition for header extraction techniques, amplitude multiplexing (all level conversion) for increasing spectral efficiency or label/payload encoding techniques, and waveform generation for radar and display applications. Existing photonic DAC techniques utilize coherent optical summation however this requires accurate control of the phases of the signals to be summed or combined. A further technique uses non linear-optical-loop mirrors (NOLMs) interferometer switches and a probe signal comprising an optical pulse to produce quaternary amplitude shift key optical signal from a binary amplitude shift key signal, in the 2-bit implementation. However this scheme requires a separate probe signal, the generation of which is not integrable with the rest of the DAC photonic circuitry.